Wouldn't want to wet that bed, it would disintegrate overnight.

I'm sure if they swapped cardboard for thin plywood that bed base would be indestructible.

My bed is 8 concrete blocks for a base with oversize pallets topped off with a panel of 2"/50mm celotex. On the base I have a thin eiderdown. Voila, it has the same feel as a physio bench and can probably take the weight of an elephant!

The lengths you have to go to when your back is wrecked :)